TransCanada to Offer TC PipeLines, LP Units

CALGARY, Alberta – March 15, 2005 – (TSX: TRP) (NYSE: TRP) – TransCanada Corporation (TransCanada) today announced that subsidiaries of TransCanada intend to sell 3,500,000 common units of TC PipeLines, LP (the Partnership). The Partnership has commenced an offering of common units owned by its general partner and an affiliate, both indirect subsidiaries of TransCanada. The underwriters have the option to purchase up to 525,000 additional units on the same terms and conditions to the extent more than 3,500,000 common units are sold in the offering.

TransCanada intends to use the net proceeds from the sale to assist in funding its 2005 capital requirements as well as for other corporate purposes. The Partnership will not receive any of the proceeds from the common units sold by TransCanada.

After the offering, subsidiaries of TransCanada will continue to own the Partnership’s general partner interest as well as approximately 12 per cent of the Partnership’s common units, assuming the underwriters’ over-allotment option is not exercised.

Citigroup Global Markets Inc. and Lehman Brothers Inc. are acting as joint book-running managers of the offering. The remainder of the underwriting group is comprised of Goldman, Sachs & Co., UBS Securities LLC and A.G. Edwards & Sons, Inc.

A copy of the preliminary prospectus supplement and related base prospectus for the offering can be obtained from Lehman Brothers Inc., c/o ADP Financial Services, Integrated Distribution Services, 1155 Long Island Avenue, Edgewood, NY 11717, email: monica_castillo@adp.com, or from Citigroup Global Markets Inc., 140 58th Street, Brooklyn, NY 11220, Attention: Prospectus Dept.

This news release does not constitute an offer to sell or a solicitation of an offer to buy the limited partnership interests described herein, nor shall there be any sale of these limited partnership interests in any state or jurisdiction in which such an offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. The offering may be made only by means of a prospectus and related prospectus supplement.

TransCanada is a leading North American energy company. TransCanada is focused on natural gas transmission and power services with employees who are expert in these businesses. TransCanada’s network of approximately 41,000 kilometres (25,600 miles) of pipeline transports the majority of Western Canada’s natural gas production to the fastest growing markets in Canada and the United States. TransCanada owns, controls or is constructing more than 5,100 megawatts of power generation – enough to meet the electricity needs of about 5.1 million average households. The Company’s common shares trade under the symbol TRP on the Toronto and New York stock exchanges.

Note: All financial figures are in Canadian dollars unless otherwise noted.

FORWARD-LOOKING INFORMATION

Certain information in this news release is forward-looking and is subject to important risks and uncertainties. The results or events predicted in this information may differ from actual results or events. Factors which could cause actual results or events to differ materially from current expectations include, among other things, the ability of TransCanada to successfully implement its strategic initiatives and whether such strategic initiatives will yield the expected benefits, the availability and price of energy commodities, regulatory decisions, competitive factors in the pipeline and power industry sectors, and the current economic conditions in North America. For additional information on these and other factors, see the reports filed by TransCanada with Canadian securities regulators and with the United States Securities and Exchange Commission. TransCanada disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

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For further information, please contact:

Media Inquiries:
TransCanada
Kurt Kadatz / Hejdi Feick
(403) 920-7859 or Toll Free (800) 608-7859

Investor & Analyst Inquiries:
David Moneta
(403) 920-7911